A rotating electric machine including a stator has conventionally been known.
For example, Japanese Patent Laying-Open No. 2004-15957 discloses an electric motor (rotating electric machine) in which a stator having a stator core is press-fit in a housing (case).
Further, Japanese Patent Laying-Open No. 2000-166207 discloses a brushless fan motor having a rubber vibration isolator provided at a portion of contact between a case containing a stator and another casing.
Furthermore, Japanese Patent Laying-Open No. 9-168253 discloses a bearing structure for a motor with the intention of suppressing vibration and mechanical noise.
Moreover, a paper of issue number 16748 in Toyota Technical Publications published on Apr. 28, 2005 discloses a technique regarding a securing structure for an IPM (Interior Permanent Magnet) motor, for reducing vibration and noise by allowing a stator core and a high stiffness portion of a motor case to selectively abut on each other.
In the case where a stator is fit in a case so that the position where the stator is attached is determined, vibration of the stator caused when a rotating electric machine is driven is likely to be transmitted to the case.
Here, if the tolerance in fitting the stator is increased, the amount of eccentricity between the stator and the rotor is likely to be increased. As a result, imbalance in the electromagnetic attraction force occurs and accordingly vibration and noise increase. Further, if the amount of eccentricity between the stator and the rotor is particularly large, there is the concern that interference between the stator and the rotor might occur.
In contrast, if the tolerance in fitting the stator is decreased, the working efficiency in inserting the stator into the case is deteriorated. Further, the area of contact between the case and the stator increases, and accordingly vibration of the stator without being damped is likely to be transmitted to the case.